This invention is concerned with polymer compositions, including polymer latices, floor polish vehicle compositions and floor polish compositions having improved high speed burnish response. The polymer compositions of this invention comprise an aqueous suspension or dispersion of a water insoluble polymer of ethylenically unsaturated monomers, said polymer having a glass transition temperature (Tg) of at least 35xc2x0 C. and comprising units of iso-butyl methacrylate (IBMA) and n-butyl methacrylate (BMA).
Ionically crosslinked floor polish vehicle compositions are well known in the prior art. Such a polish vehicle composition comprises a polymer latex, comprising an aqueous dispersion or suspension of water insoluble, film forming polymer having a Tg above room temperature, and water soluble or dispersible metal salts and complexes. The nature of the polymer is determined inter alia by the intended use of the vehicle. For example, a floor polish vehicle includes a polymer useful on flooring materials and which will withstand pedestrian traffic. Floor polish compositions comprise floor polish vehicle compositions together with other useful floor polish ingredients such as alkali soluble resins, plasticizers, waxes, preservatives, dispersing agents, coalescents and leveling agents.
One important characteristic of a floor polish composition is its resistance to deterioration from pedestrian traffic. The greater its resistance, the more durable the floor polish is said to be. Good durability is defined as the ability of a finish layer to repel scuff and black heel marks. The general property of durability can be measured in a variety of ways. For example, scuff and scratch resistance, retention of film gloss, powder resistance, soil resistance, and black heel mark resistance are all well recognized in the floor polish art as indications of durability. The factors effecting the durability of a floor polish composition are described in detail in U.S. Pat. No. 4,517,330.
Another characteristic desirable in a floor polish composition is the ability to affect repair of damage, caused on the floor finish by pedestrian traffic, by the action of high speed buffing or burnishing, thereby periodically returning the floor finish to its original appearance. The capacity of a floor finish to be restored by the mechanical action of a high speed burnishing machine is referred to as its xe2x80x9cburnish response.xe2x80x9d The use of these floor polish compositions along with regular burnishing provides high gloss appearance over extended periods of time, thereby eliminating or substantially reducing the need for costly stripping and recoat operations typically encountered with conventional floor polishes.
Burnishable floor polish compositions typically employ high levels of soft waxes and/or high levels of plasticizer, to soften the floor finish or otherwise diminish the resistance of the film to the abrasive action of the burnishing pad, thus making it more receptive to film repair by the burnishing operation. However, because of the softness of the finish layer, these floor polishes require frequent burnish maintenance to restore them to their original xe2x80x9cwet lookxe2x80x9d appearance. The ability of a finish layer to be repeatedly restored to a high gloss finish during the burnish operation is a measure of a floor""s xe2x80x9crepeatable burnish response.xe2x80x9d With the more general acceptance of ultra high speed burnishing machines, these types of floor polish compositions have become more commercially important. Good repeatable burnish response is one of the properties especially desirable, but not exclusive to, high gloss floor polishes destined for use in a retail outlet, such as a supermarket.
It is known that polymer latices formed from IBMA and other ethylenically unsaturated monomers, namely styrene (Sty), methyl methacrylate (MMA) and methacrylic acid (MAA), are used in floor polish compositions and that these compositions demonstrate good initial gloss and good repeatable burnish response over conventional floor polishes.
It is one object of the present invention to provide new polymer latices and polish vehicle compositions which may be used to produce a floor polish composition which is capable of demonstrating at least an equivalent repeatable burnish response without any detrimental effect on either the high initial gloss or the durability of the finish layer. Preferably, such compositions should demonstrate improved high initial gloss and improved repeatable burnish response without any detrimental effect on the durability.
Floor polish compositions based on aqueous dispersions of water insoluble emulsion copolymers containing acid functional residues and polyvalent metal ion or complex crosslinking agents are well known in the prior art. Such compositions are disclosed in U.S. Pat. Nos. 3,328,325, 3,467,610, 3,554,790, 3,573,329, 3,711,436, 3,808,036, 4,150,005, 4,517,330, 5,149,745, 5,319,018. None of these documents specifically disclose polymer latices comprising copolymers formed from mixtures of ethylenically unsaturated monomers including both IBMA and BMA, nor does any one of them specifically address the problem of obtaining a good repeatable burnish response in a floor polish.
Japanese patent application No 01-261843 discloses nonaqueous dispersion type resin compositions for construction facings, but there is no suggestion that these compositions could be useful as floor polish vehicle compositions, let alone that they may be capable of imparting high speed burnish response in a floor polish composition. Further, the resins specifically disclosed in this document comprise IBMA and BMA in amounts where the IBMA content is equal to or more than the BMA content.
In accordance with one aspect of the present invention, there is provided a polymer composition comprising an aqueous suspension or dispersion of a water insoluble polymer of ethylenically unsaturated monomers, said polymer having a Tg of at least 35xc2x0 C. and comprising 25% to 65% by weight units of IBMA and BMA and 3% to 50% by weight units of at least one acidic monomer. In one embodiment of this particular aspect of the present invention, there is provided a polymer composition comprising an aqueous suspension or dispersion of a water insoluble polymer having a Tg of at least 35xc2x0 C. and formed from a mixture of ethylenically unsaturated monomers comprising 25% to 65% by weight IBMA and BMA and 3% to 50% by weight of at least one acidic monomer. In another embodiment of this particular aspect of the present invention, there is provided a polymer latex comprising an aqueous suspension or dispersion of a water insoluble polymer having a Tg of at least 35xc2x0 C. and formed from a mixture of ethylenically unsaturated monomers comprising 25% to 65% by weight IBMA and BMA and 3% to 50% by weight of at least one acidic monomer. In another embodiment of this particular aspect of the present invention, there is provided a floor polish vehicle composition comprising an aqueous suspension or dispersion of a water insoluble polymer having a Tg of at least 35xc2x0 C. and formed from a mixture of ethylenically unsaturated monomers comprising 25% to 65% by weight IBMA and BMA, and 3% to 50% by weight of at least one acidic monomer. In yet another embodiment of this particular aspect of the present invention, there is provided a floor polish composition comprising an aqueous suspension or dispersion of a water insoluble polymer having a Tg of at least 35xc2x0 C. and formed from a mixture of ethylenically unsaturated monomers comprising 25% to 65% by weight IBMA and BMA, and 3% to 50% by weight of at least one acidic monomer.
In another aspect of this invention, there is provided a method for improving the repeatable high speed burnish response of a floor polish composition, which method comprises using in the composition a floor polish vehicle composition comprising an aqueous suspension or dispersion of a water insoluble polymer of ethylenically unsaturated monomers, said polymer having a Tg of at least 35xc2x0 C. and comprising 25% to 65%, preferably 35% to 55%, by weight units of IBMA and BMA, and 3% to 50%, preferably 5% to 20%, by weight units of at least one acidic monomer.
Surprisingly, it has been found that floor polish compositions comprising an aqueous suspension or dispersion of a water insoluble polymer in accordance with the invention may be capable of demonstrating both improved initial gloss and repeatable high speed burnish response without detrimental effects on the durability of the polish.
Preferably, the water insoluble polymer has a Tg of at least 40xc2x0 C.
The water insoluble polymer is preferably formed from a monomer mix comprising 25% to 65%, preferably 35% to 55%, by weight IBMA and BMA; 0% or up to 70%, preferably 25% to 50%, by weight of at least one vinyl aromatic monomer; 3% to 50%, preferably 5% to 20%, by weight of at least one acidic monomer; and 0% or up to 72%, preferably 0% or up to 35%, by weight of at least one monomer selected from the acrylic and methacrylic acid esters of (C1-C8) alcohols which are not IBMA or BMA, and 0% or up to 40%.
Preferably, the amount of IBMA in the monomer mix constitutes no more than 80% by weight, more preferably less than 50% by weight, and yet more preferably no more than 30% by weight of the total weight of IBMA and BMA in the mix. Preferably, the amount of IBMA in the monomer mix constitutes at least 5% by weight, more preferably at least 20% by weight, and yet more preferably at least 50% of the total weight of IBMA and BMA in the mix.
Preferably, the vinyl aromatic monomer(s) is/are alpha, beta ethylenically unsaturated aromatic monomers and is/are preferably selected from the group consisting of styrene (Sty), vinyl toluene, 2-bromo styrene, o-bromo styrene, p-chloro styrene, o-methoxy styrene, p-methoxy styrene, allyl phenyl ether, allyl tolyl ether and alpha-methyl styrene. Sty is the most preferred monomer.
Preferably, the acidic monomer(s) is/are alpha, beta monoethylenically unsaturated acids and is/are preferably selected from the group consisting of maleic acid, fumaric acid aconitic acid, crotonic acid, citraconic acid, acryloxypropionic acid, acrylic acid, methacrylic acid (MAA) and itaconic acid. MAA is the most preferred. Other acidic monoethylenically unsaturated monomers that may be copolymerized to form the water insoluble, film forming polymers are partial esters of unsaturated aliphatic dicarboxylic acids and the alkyl half esters of such acids. For example, the alkyl half esters of itaconic acid, fumaric acid and maleic acid wherein the alkyl group contains 1 to 6 carbon atoms such as methyl acid itaconate, butyl acid itaconate, ethyl acid fumarate, butyl acid fumarate and methyl acid maleate.
In addition to IBMA and BMA, the monomer mix may comprise 0% or up to 72% of at least one monomer selected from the acrylic and methacrylic acid esters of (C1-C8) alcohols which are not IBMA or BMA, such as methyl methacrylate (MMA), methyl acrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate (BA), 2-ethyl hexyl acrylate, n-octyl acrylate, sec-butyl acrylate, and cyclopropyl methacrylate.
The monomer mix may also comprise 0% or up to 40% by weight of at least one polar or polarizable nonionogenic hydrophilic monomer, such as acrylonitrile, methacrylonitrile, cis- and trans-crotononitrile, alpha-cyanostyrene, alpha-chloroacrylonitrile, ethyl vinyl ether, isopropyl vinyl ether, isobutyl- and butyl-vinyl ether, diethylene glycol vinyl ether, decyl vinyl ether, vinyl acetate, hydroxyalkyl (meth) acrylates such as 2-hydroxy ethyl methacrylate, 2-hydroxyethyl acrylate, 3-hydroxy propyl methacrylate, butanediol acrylate, 3-chloro-2-hydroxypropyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, and vinyl thiols such as 2-mercaptopropyl methacrylate, 2-sulphoethyl methacrylate, methyl vinyl thiol ether and propyl vinyl thio ether.
The monomer mix may also comprise 0% or up to 10% by weight of at least one monomeric vinyl ester in which the acid moiety of the ester is selected from the aromatic and (C1 to C18) aliphatic acids. Such acids include formic, acetic, propionic, n-butyric, n-valeric, palmitic, stearic, phenyl acetic, benzoic, chloroacetic, dichloroacetic, gamma-chloro butyric, 4-chlorobenzoic, 2,5-dimethyl benzoic, o-toluic, 2,4,5-trimethoxy benzoic, cyclobutane carboxylic, cyclohexane carboxylic, 1-(p-methoxy phenyl)cyclohexane carboxylic, 1-(p-tolyl)-1-cyclopentane carboxylic, hexanoic, myristic, and p-toluic acids. The hydroxy vinyl moiety of the monomer may for example be selected from hydroxy vinyl compounds such as hydroxy ethylene, 3-hydroxy-pent-1-ene, 3,4-dihydroxybut-1-ene, and 3-hydroxy-pent-1-ene, it being understood that such derivation can be purely formal such as in the case of the vinyl acetate monomer in which the compound may be considered to be derived from acetic acid and hydroxy ethylene, although the monomer cannot in fact be prepared from such a precursor compound.
The process for the preparation of the aqueous dispersible water insoluble polymers of this invention is well known in the art. The practice of emulsion polymerization is discussed in detail in D. C. Blackley, Emulsion Polymerization (Wiley, 1975). The latex polymers of this invention may also be formulated using internally plasticized polymer emulsions. Preparation of internally plasticized polymer emulsions is described in detail in U.S. Pat. No. 4,150,005 and the preparation of non-internally plasticized floor polish emulsion polymers is described in U.S. Pat. Nos. 3,573,239, 3,328,325, 3,554,790 and 3,467,610.
Conventional emulsion polymerization techniques as described above may be used to prepare the polymer latices of this invention. Thus the monomers may be emulsified with anionic or nonionic dispersing agents; about 0.5% to 10% thereof on the weight of total monomers preferably being used. Acidic monomers are water soluble and thus serve as dispersing agents which aid in emulsifying the other monomers used. A polymerization initiator of the free radical type, such as ammonium or potassium persulphate, may be used alone or in conjunction with an accelerator, such as potassium metabisulphate or sodium thiosulphate. The initiator and accelerator, commonly referred to as catalysts, may conveniently be used in proportions of 0.5% to 2% each based on the weight of monomers to be copolymerized. The polymerization temperature may for example be from room temperature to 90xc2x0 C., or more, as is conventional.
Examples of emulsifiers which are suited to the polymerization process of emulsions useful in this invention include alkaline metal and ammonium salts of alkyl, aryl, alkaryl and aralkyl sulphonates, sulphates and polyether sulphates; the corresponding phosphates and phosphonates; and alkoxylated fatty acids, esters, alcohols, amines amides and alkylphenols.
Chain transfer agents, including mercaptans, polymercaptans and polyhalogen compounds are often desirable in the polymerization mixture to control polymer molecular weight.
The floor polish vehicle composition preferably comprises the water insoluble polymer as defined in any embodiment above, 0% or up to 100% of the equivalents of the acid residues in the polymer of at least one polyvalent metal ion or complex crosslinking agent and optionally at least one basic hydroxide or salt of an alkali metal, as taught in U.S. Pat. No. 4,517,330. Preferably, the polyvalent metal is a transition metal. A floor polish vehicle composition wherein the transition metal ion or complex crosslinking agent content is from 25% to 80% of the equivalent of the acid residues in the polymer and/or the molar ratio of transition metal content is from 1.0:0.25 to 1.0:2.0 is preferred. Still more preferred is a composition wherein the transition metal content is from 30% to 70% of the equivalent of the acid residues in the polymer and/or the molar ratio of transition to alkali metal is from 1.0:0.5 to 1.0:1.5.
The polyvalent and alkali metal ion and complex crosslinking agents useful in the present invention are well known in the art. These are described in for example, U.S. Pat. Nos. 3,328,325, 3,328,325, 3,467,610, 3,554,790, 3,573,329, 3,711,436, 3,808,036, 4,150,005, 4,517,330, 5,149,745, 5,319,018. The preferred polyvalent metal complexes include the diammonium zinc (II) and tetra-ammonium zinc (II) ions, cadmium glycinate, nickel glycinate, zinc glycinate, zirconium glycinate, zinc alanate, copper beta-alanate, zinc beta-alanate, zinc valanate, copper bis-dimethylamino acetate.
The polyvalent and alkali metal ion and complex crosslinking compounds are readily soluble in the aqueous medium of the polish vehicle composition, especially at a pH in the range 6.5 to 10.5. However, the polish composition containing these compounds dries to form a polish deposit which is essentially insoluble in water but still removable. The polyvalent metal complex may also be added as a solution to the water insoluble film forming polymer latex. This may be accomplished by solubilizing the metal complex in an alkaline solution such as dilute ammonia. Since the ammonia may complex with the polyvalent metal compound, a compound such as cadmium glycinate, when solubilized in an aqueous ammonia solution may be named cadmium ammonia glycinate. Other polyvalent metal complexes described may be similarly named.
Although, to be suitable, the polyvalent metal complex must be stable in an alkaline solution, a complex that is too stable is undesirable because dissociation of the metal ion would then be retarded during the film formation of the polish coating.
The floor polish composition should preferably have a minimum film forming temperature (MFT) of less than 100xc2x0 C. and more preferably less than 80xc2x0 C.
The polyvalent metal ion and complex crosslinking agent may be incorporated into the polish composition at any stage of its formulation. Although generally it is convenient to add it in the floor polish vehicle.
Similarly, the basic salt of the alkaline metal may be incorporated with the polyvalent metal ion and complex crosslinking agent at any stage of the polish formulation. Although it is generally more convenient to add the alkali metal basic salt in a common solution with the polyvalent metal ion and complex crosslinking agent into the floor polish vehicle composition.
In general, the floor polish compositions of the present invention will comprise the following main components:
a) 10-100 parts by solids weight water insoluble polymer which has been previously or subsequently crosslinked with a polyvalent metal complex and/or alkali metal basic salt;
b) 0-90 parts by solids weight wax emulsion;
c) 0-90 parts by solids weight alkali soluble resin (ASR)
d) 0.01-20 parts by weight wetting, emulsifying and dispersing agents, defoamer, leveling agent; plasticizers and coalescing solvents, sufficient for polish film formation at application temperature;
e) water, sufficient to make total polish solids 0.5% to 45%, preferably 5% to 30%.
The total of a), b) and c) should be 100.
The amount of c), when present may be up to 100% of a) and is preferably from 3% to 25% of the weight of a). Satisfactory floor polish formulations have been prepared without the inclusion of an ASR. Thus, an ASR is not an essential component of a durable floor polish composition. Depending on the properties inherent to the polish vehicle composition and other formulation ingredients (d), the ASR may optionally be employed to moderately reduce total formulation costs, improve leveling and gloss properties, and increase the polish sensitivity to alkaline strippers, depending upon the ultimate balance of properties desired by the polish formulator and qualities of ASR.
For a high speed burnish polish composition, such as those of the present invention, the wax level should preferably be more than 6% by weight of the total solids of a), b) and c).
Conventional wetting agents, dispersing agents, defoamers, plasticizers and coalescing solvents may be used in conventional amounts, depending upon the balance of performance properties desired by the formulator. Other formulation ingredients, such as perfumes or odor-masking agents, dyes or colorants, bacteriocides and bacteriostats, may also be optionally included by the formulator.